The invention is generally in the field of immunotoxins, particularly immunotoxins effective against pathogenic cells, e.g., cancer cells.
Immunotoxins are multifunctional (e.g., bifunctional) molecules that contain domains that direct the molecules to target cells of interest (e.g., cancer cells) and toxic domains that kill the target cells. They are thus useful in pathological conditions such as cancer, autoimmune diseases, and certain infectious diseases. The field of immunotoxins has been limited by an inability to escalate the dose of immunotoxin administered to a subject to a level that is therapeutic but not unacceptably toxic.